The long-term objectives of this collaborative research project are to conduct a careful systematical study of T. (S). taiwani which will investigate its public health significance as a potential parasite of humans in Taiwan, life cycle, relationships to other members of the Schizotrypanum at the biological and molecular levels, immunological interactions with laboratory hosts, and usefulness as a laboratory model of chronic infection. The research will enhance our knowledge of this subgenus of trypanosomes and may describe an unrecognized disease of animals and/or humans caused by the parasite in Asia. The proposed study and the activities during visits to Taiwan are described in Section 29b. The research is designed to: validate the identify of T. (S). taiwani currently maintained in laboratories in Kaohsiung and Terre Haute by reisolation of the trypanosome (1st year), perform serological screens on blood specimens of hospitalized patients from diverse areas of Taiwan (1st - 3rd years), examine possible vectors of the parasite (1st year), survey other wild and domestic animals as possible hosts (2nd year), define the relationships to other trypanosomes through peptideme (proteins), schizodeme (kDNA/mitochondrial DNA), zymodeme (isoenzymes) and antigenic analyses (current and continuing, with reanalysis after validation), and characterize infections in strains of laboratory mice and define the responses which allow host survival, but permit persistent parasitemias (2nd year and continuing after the period of requested support). The times indicated above represent 3- month visit during the 1st, 2nd, and 3rd years of Fellowship support. Continuity, oversight, and communication during the project demand consistent attention of the applicant allowed by these visits.